JP2002013082A - Rubber-steel cord composite - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To obtain a stable adhesive strength. SOLUTION: The rubber-steel cord composite of the present invention comprises a rubber component composed of a natural rubber and / or a synthetic rubber and 100 parts by weight of the rubber component, and contains 0.1 to 1 inorganic hydrate.
A rubber composition comprising 0 parts by weight and 3 to 8 parts by weight of sulfur, and a steel filament having a copper (Cu) concentration of 15 to 45 atomic% on its peripheral surface and a brass plated steel filament. 15 nm inside the filament in the radial direction
, And a brass-plated steel filament containing at least one of cobalt (Co) atoms and nickel (Ni) atoms in a surface layer region up to the depth of, or a steel cord obtained by twisting the filaments.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber-steel cord composite, and more particularly, to a method in which a surface of a cord plating is coated with Co.
The present invention relates to a technique for improving the adhesiveness by containing atoms or Ni atoms and making a rubber composition a specific compound.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 9-216768 discloses a technique in which an inorganic hydrate is blended in order to supply water during kneading or vulcanization, and the adhesive strength and heat aging characteristics after vulcanization are improved. Have been. However, when the rubber composition blended with the inorganic hydrate is used for forming a composite with a steel cord, if the blended rubber is left in the air at room temperature for a long time, the initial adhesive strength is disadvantageously reduced. There is.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rubber-steel cord composite which stably exhibits a high adhesive strength and which does not lose its adhesiveness even after long-term storage. .

[0004]

During long-term storage, the adhesive strength and various physical properties of the vulcanized rubber change because the inorganic hydrate gradually reacts with the Co salt or Ni salt in the rubber gradually. Conceivable. By combining with steel cord containing Co during brass plating (including steel filament (monofilament cord)), inorganic hydrate and Co
The inventors considered that the reaction with the salt was suppressed, and as a result of investigation, found that a high adhesive strength could be obtained even after long-term storage, and completed the present invention.

[0005] The constitution of the rubber-steel cord composite of the present invention is as follows. (1) A rubber component composed of natural rubber and / or synthetic rubber and 100 parts by weight of the rubber component are mixed with 0.1 parts of inorganic hydrate.
1010 parts by weight and 3-8 parts by weight of sulfur, and a steel filament whose peripheral surface has been subjected to brass plating with a Cu concentration of 15-45 atomic% on the peripheral surface. It consists of a brass-plated steel filament alone containing at least one of Co atoms and Ni atoms in the surface layer region up to a depth of 15 nm inward in the direction, or a steel cord obtained by twisting the filament.

(2) The rubber component is characterized in that at least 50% by weight is natural rubber. (3) The synthetic rubber is at least one selected from the group consisting of styrene / butadiene rubber, butadiene rubber, butyl rubber, halogenated butyl rubber, butyl rubber having a paramethylstyrene group, ethylene / propylene / diene rubber, and isoprene rubber. It is characterized by the following. (4) The styrene-butadiene rubber has a butadiene portion having a vinyl bond amount of 35 to 85% by weight and a bond styrene amount of 30% by weight or less.
It is a butadiene rubber.

(5) The butadiene rubber has a vinyl bond amount of 1 to 85% by weight. (6) The total amount of Co atoms and Ni atoms contained in the surface region is 0.1 atomic% or more and C in the surface region
It is not more than the content of u atoms. (7) The total amount of Co atoms and Ni atoms contained in the surface layer region is 0.5 to 5.0 atomic%. (8) In the surface region, the amount of Co atoms and Ni atoms not included in the oxide is 50 atomic% or more of the total amount of Co atoms and Ni atoms contained in the surface region. (9) The average thickness of the brass plating is 0.13 to 0.30 μm. (10) The diameter of the filament is 0.40 mm or less.

[0008]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail. Also,
With respect to 100 parts by weight of the rubber component, 0.1 to
It is stipulated that 10 parts by weight be blended. If the amount is less than 0.1 part by weight, there is no effect of improving the adhesiveness. It is not preferable because the characteristics are deteriorated. When the amount is 0.2 to 8 parts by weight, more preferably 0.3 to 3 parts by weight, it is more effective.

The inorganic hydrate preferably used in the present invention is
The NiSO_Four・ 7H_TwoO, CoSO_Four・ 7H_TwoO, Na
SO_Four・ 10H_TwoO, CaSO₄・ 2H_TwoO, CuSO_Four・
5H _FourO, Al_Two(SO₄)_Three・ 18H_TwoO, FeSO_Four・
7H_TwoO, ZnSO_Four・ 7H_TwoO, MgSO_Four・ 7H_TwoO,
Na_TwoS ・ 9H_TwoO, Na_ThreePO_Four・ 12H_TwoO, NaH_TwoP
O_Four・ 2H_TwoO, Na_TwoHPO_Four・ 12H_TwoO, Ni_Three(PO
_Four)_Two・ 8H_TwoO, Mg_Three(PO_Four)_Two・ 8H_TwoO, Li_ThreePO
_Four5H_TwoO, Na_FourP_TwoO₇・ 10H_TwoO, Ni_TwoP_TwoO ₇・ 6
H_TwoO, Mn_Four(P_TwoO₇)_Three・ 14H_TwoO, CoCO_Three, 6H
_TwoO, NiCO_Three・ 6H_TwoO, Na_TwoCO_Three・ 10H_TwoO, N
d_Two(CO_Three)_Three・ 8H_TwoO, Na₂SO_Three・ 7H_TwoO, Ca
_TwoCl_Two・ 6H_TwoO, NiCl_Two・ 6H_TwoO, NaB_FourO₇・
10H_TwoO, FeCl_Three・ 6H_TwoO, Na_TwoSiO_Three・ 9H_Two
O and the like.

[0010] Further, it is specified that the natural rubber is contained in the rubber component in an amount of 50% by weight or more. If the amount is less than 50% by weight, the adhesive property and the rubber breaking property are deteriorated, which is not preferable.

Among the rubber components of the present invention, the synthetic rubbers include styrene-butadiene rubber (SBR), butadiene rubber (BR), butyl rubber (IIR), halogenated butyl rubber, especially brominated butyl rubber, and p-methylstyrene. Butyl rubber (specifically, a copolymer of isobutylene and p-halogenated methylstyrene, etc.), ethylene-propylene-diene rubber (EPDM), and isoprene rubber (IR) are preferable in terms of heat aging resistance.

Further, of the SBR, the vinyl bond content is 35%.
~ 85% by weight and the amount of bound styrene is 30% by weight
The following, solution-polymerized SBR is preferred, which has a good balance between the heat aging resistance and the breaking properties of the rubber composition when the vinyl bond amount is 35 to 85% by weight, and has a combined styrene amount of 30% by weight. % Or less, the adhesiveness is more excellent. In the case of BR, the vinyl bond amount is 1 to 85.
When it is% by weight, the rubber composition has a great merit of heat aging resistance and is excellent in breaking characteristics, so that it is preferable.

Further, it is specified that 3 to 8 parts by weight of sulfur is blended with respect to 100 parts by weight of the rubber component, but if the amount is less than 3 parts by weight, it is difficult to secure the original adhesive force of sulfur-rubber vulcanization bonding. This is because it is a range, and if it exceeds 8 parts by weight, the heat aging resistance and the heat resistant adhesive properties of the rubber are reduced, which is not preferable.

Further, in the present invention, in addition to the above components, a compounding agent usually used in the rubber industry can be appropriately compounded. Specifically, based on 100 parts by weight of the rubber component, 2 to 10 parts by weight of zinc white, 0.3 to 2 parts by weight of a vulcanization accelerator, 30 to 70 parts by weight of carbon black, and 30 parts by weight of an adhesion promoter 0.25 to 3 parts by weight, etc., which means that when zinc white is less than 2 parts by weight with respect to 100 parts by weight of the rubber component,
When the rubber elastic modulus is not sufficiently obtained, the adhesiveness is reduced when the amount exceeds 10 parts by weight, and when the vulcanization accelerator is less than 0.3 parts by weight, a sufficient rubber elasticity is not obtained, and when the amount exceeds 2 parts by weight, When the adhesion is reduced and carbon black is less than 30 parts by weight, a sufficient rubber elastic modulus cannot be obtained, and when it is more than 70 parts by weight, the destructive properties are reduced. Is not obtained, and when it exceeds 3 parts by weight, heat aging resistance is inferior.

[0015] The inventors of the present invention have used brass plating, which is usually used in order to clarify the relationship between the component composition in the depth direction from the plating surface and the initial adhesiveness of the brass plating applied to the peripheral surface of the filament. Co ions were implanted into the plating filaments to examine the adhesion to the coated rubber with the adhesion promoter reduced or not added. That is, using the ion plantation technique, the relationship between the ion implantation time and the Co content on the surface of the brass plating and the relationship between the ionization rate and the depth direction distribution of the Co content shown in FIG. 1 are grasped in advance. Then, the Co content of the plating surface layer was variously controlled, and the relationship with the initial adhesiveness was investigated.

As a result, it was newly found that the inclusion of Co to a depth of 15 nm from the plating surface was most effective for improving the initial adhesion, and the present invention was completed. That is, the initial adhesion was evaluated by expanding the Co-containing region in the depth direction from the plating surface and evaluating the initial adhesion at various stages of the enlarging process of the region. As the Co-containing region was expanded in the depth direction, the initial adhesion increased. It was found that even if the Co-containing region was expanded to a depth exceeding 15 nm, the initial adhesiveness was not further improved, and the effect was saturated at a depth of 15 nm. did.

On the other hand, when the initial adhesion was similarly evaluated by increasing the Co content only on the plating surface, if the Co was not diffused to a certain depth, the effect of improving the initial adhesion was small, It was also found that the initial adhesion to the coated rubber with reduced or no added metal salt was not at a level that would ensure it.

Further, when the Co content in the surface layer region from the plating surface to a depth of 15 nm was examined, if the content was less than 0.1 atomic%, the effect of improving the initial adhesion was poor, while the effect of the surface region was poor. When the Cu content is exceeded, the effect of improving the initial adhesiveness is saturated.
It is preferable that the content be in the range of 0.1 atomic% or more and the Cu content of the surface layer region or less. More preferably, 0.5 to
It is recommended to be in the range of 5.0 atomic%.

When Co is contained only in the surface layer up to a depth of 15 nm from the plating surface, if ion implantation is used, as shown in FIG. It will show a concentration gradient that gradually decreases in the direction. In this case, as described below, the Co content in the surface layer region is obtained by creating a depth profile as shown in FIG. 3 by using X-ray photoelectron spectroscopy (XPS) to obtain Cu, Zn, and Co in the entire surface region. C for total atomic amount
o It is obtained by calculating the atomic% amount. The same applies to the Ni content.

The reason that the initial adhesion is improved by containing Co in the surface layer region up to a depth of 15 nm from the plating surface is that Co is diffused from the plating surface to a depth of 15 nm before the vulcanization bonding. This is because effective diffusion of Cu inside the plating can be realized. Further, even if Co diffuses into the region exceeding this depth during plating, it is clear that the effect is saturated, and the cost increases due to an increase in Co. The above findings were not limited to Co, but were similar for Ni.

As described above, the ion implantation technique was used to contain Co in the depth direction from the plating surface. However, when other methods of inserting Co or Ni into the surface layer region of the brass plating were examined, it was found that the brass plating was The applied filament is, for example, 5 to 100 parts by weight of water per liter of water.
After repeating the process of immersing in a colloid in which 10 parts by weight of a cobalt metal salt and an appropriate surfactant are dispersed and drying, and then performing a heat treatment at a temperature of 150 ° C. to 250 ° C., the Co can be formed to a depth of 15 nm. Was able to diffuse to the inside of the plating. At this time, the cobalt content of the surface layer can be adjusted by controlling at least one of the number of times of dipping the cord in the liquid, the number of times of drying, and the number of times of thermal diffusion. FIG. 2 shows an example of the result of elemental quantification of Cu, Zn, and Co in the plating depth direction of the filament manufactured as described above using photoelectron spectroscopy.
Shown in

Similarly, when producing a steel cord, in the step of drawing a filament, an appropriate amount of a metal salt of Co or Ni as an adhesion promoter is added to a lubricant, and heat generated during drawing is used. It is also possible to diffuse Co or Ni to the inside of the 15 nm plating.

Next, the Cu content on the plating surface was studied diligently. That is, the basic composition of plating is
In addition to the initial adhesiveness, it is necessary to consider adhesion durability such as heat resistance and humidity resistance after rubber vulcanization, and from the viewpoint of adhesion durability, the Cu content on the outermost surface is 45 atomic% or less, preferably It must be limited to 40 atomic% or less. On the other hand, in order to secure the initial adhesiveness, it is necessary to contain a certain amount or more of Cu, and the Cu content is made 15 atomic% or more, preferably 25 atomic% or more.

FIG. 3 shows a typical example of the concentration distribution of each component in the plating depth direction, including the plating surface layer region, when the basic plating composition and the Co content are regulated according to the present invention.

Further, Co and Ni contained in the surface layer
It is preferable that 50 atomic% or more of the total amount of Co is Co and / or Ni not contained in the oxide. This is because cobalt oxide or the like combined with oxygen is very stable due to its strong bond, and makes it impossible for Co or Co ions to diffuse or move in the metal. As a result, the exchange reaction and the substitution reaction between Co and Cu do not proceed, and cannot play a role as an adhesion promoter.

The amount of Co or Ni not contained in the oxide contained in the surface layer region is determined based on the result of measuring the plating surface by X-ray photoelectron spectroscopy, for example, as shown in FIG. Can be determined from the area ratio between the oxide and the metal from the abundance ratio of both.

Further, the average thickness of the brass plating is 0.1
Advantageously, it is between 3 and 0.30 μm. That is,
When the average plating thickness is less than 0.13 μm, the portion where the iron base is exposed increases, and the initial adhesiveness is impaired.
This is because, if it exceeds, the adhesive reaction proceeds excessively due to the heat during use of the rubber article, and only fragile adhesion can be obtained.

It is advantageous that the filament diameter is 0.40 mm or less. This is because, when it exceeds 0.40 mm, when the used rubber article is repeatedly subjected to distortion under bending deformation, the surface distortion becomes large and buckling is easily caused.

The amount of Co in the plating is determined by X-ray photoelectron spectroscopy from the plating surface to a depth of 15 nm or more in terms of the etching speed of SiO _2.
While performing argon etching while monitoring characteristic photoelectrons of u, Zn, Co, O, and C, the amount of elements present at each depth i was quantified, and Cu _i atomic% and Co _i atomic% were obtained, respectively. Further, a depth profile up to 15 nm (see FIG. 3) was created, and the Co atomic% of the surface layer region was calculated from the relative areas of Cu, Zn, and Co in that region. The plating thickness is 0.25 μm
It is.

Here, Cu _i atomic% and Co _i atomic% are: Cu _i atomic% = [fcu Cu _in / (fcu Cu _in + fznZn _in + f
coCo _in )] × 100 Co _i atomic% = [fco Co _in / (fcuCu _in + fznZn _in
+ fcoCo _in )] × 100 where fcu, fzn, and fco are sensitivity coefficients of each element, and Cu
_in , Zn _in , and Co _in are count numbers of each element at the position of the depth i, and the unit is count per second.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below. According to the formulation shown in Table 1, a rubber composition was prepared and tested by the following method. The results are also shown in Table 1. In the table,
The adhesion after [drying] is the data for the rubber component, C / B, ZnO, anti-aging agent, vulcanization accelerator, and sulfur, and is data when vacuum-dried before blending. After kneading the rubber, the sample was left for 1 day, 1 week, 2 weeks, and 4 weeks in air conditioned at 25 ° C. and 50% humidity, respectively, and then measured in the same manner. is there.

Measurement of adhesive strength Brass plating (steel cord A: Cu: 63% by weight, Z
n: 37% by weight, and steel cord B is Cu: 63
% By weight, Co in the surface layer region: 1.0% by weight. ), Each steel cord (1 × 5 structure, wire diameter 0.25 mm) was arranged in parallel at 12.5 mm intervals, and the steel cord was coated from both sides with a rubber composition (composition shown in Table 1) to obtain a sample. It was created. After vulcanizing this at 160 ° C. for 20 minutes, the steel cord was pulled out in accordance with ASTM-D-2229, the pulling force at that time was measured, and the control (adhesion force of the comparative example 1 after standing for one day) was determined. The index was indicated as 100. The larger the numerical value, the higher the adhesive strength and the better.

[0033]

[Table 1] From the results shown in Table 1, it can be seen that the rubber-steel cord composite of the present invention maintains a high adhesive strength in both the adhesive strength after drying and after standing.

[0034]

As described above, the rubber-steel cord composite of the present invention can exhibit a stable adhesive force which is not affected by environmental conditions such as seasons and working conditions.

[Brief description of the drawings]

FIG. 1 is a diagram showing the distribution of the Co content in the depth direction from the plating surface to the inside when Co is injected into the brass plating surface by ion plantation.

FIG. 2 is a view showing the distribution of the Co content in the depth direction from the plating surface to the inside when the Co is immersed in a colloid containing a cobalt metal salt, dried, and thermally diffused at 200 ° C. into the inside of the plating.

FIG. 3 is a diagram showing a concentration distribution in the depth direction of each component in brass plating.

FIG. 4 is a schematic diagram of a spectrum when the state of Co on the surface of the brass plating is diffracted by X-ray photoelectron spectroscopy.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 21/00 C08L 21/00 // B60C 1/00 B60C 1/00 C 9/00 9/00 KF Terms (reference) 3B153 AA02 BB01 CC29 CC41 CC52 CC55 GG13 4F072 AA04 AB11 AD02 AD04 AE02 AF01 AF02 AF04 AL18 4J002 AC011 AC031 AC061 AC071 AC081 BB151 BB181 BB241 DA047 DD066 DD076 DE216 DE226 DG046 DH046 DJ006 006 006

Claims (10)

[Claims] 1. A rubber composition comprising a rubber component composed of a natural rubber and / or a synthetic rubber, and 0.1 to 10 parts by weight of an inorganic hydrate and 3 to 8 parts by weight of sulfur with respect to 100 parts by weight of the rubber component. And the peripheral surface has a copper (Cu) concentration of 1 on the surface.
Cobalt (Co) is added to the surface layer of the brass-plated steel filament of 5 to 45 atomic% from the surface to a depth of 15 nm radially inward from the surface.
A rubber-steel cord composite comprising a brass-plated steel filament containing at least one of atoms and nickel (Ni) atoms alone or a steel cord obtained by twisting the filaments. 2. The rubber according to claim 1, wherein 50% by weight or more of the rubber component is natural rubber.
Steel cord composite. 3. The synthetic rubber is at least one selected from the group consisting of styrene / butadiene rubber, butadiene rubber, butyl rubber, halogenated butyl rubber, butyl rubber having a paramethylstyrene group, ethylene / propylene / diene rubber, and isoprene rubber. The rubber-steel cord composite according to claim 1 or 2, wherein 4. The styrene-butadiene rubber has a butadiene portion having a vinyl bond amount of 35 to 85% by weight,
The rubber-steel cord composite according to claim 3, which is a solution-polymerized styrene-butadiene rubber having a bound styrene content of 30% by weight or less. 5. The butadiene rubber has a vinyl bond amount of 1
The rubber-steel cord composite according to claim 3, wherein the content is from about 85% by weight. 6. The method according to claim 1, wherein the total amount of Co atoms and Ni atoms contained in said surface layer region is not less than 0.1 atomic% and not more than Cu atom content in said surface layer region. The rubber-steel cord composite according to claim 1. 7. The rubber-steel according to claim 1, wherein the total amount of Co atoms and Ni atoms contained in the surface layer region is 0.5 to 5.0 atomic%. Code complex. 8. In the surface layer region, C not contained in the oxide
o atoms and Ni atoms contain C atoms contained in the surface layer region.
The rubber-steel cord composite according to any one of claims 1 to 7, wherein the total amount of the o atoms and the Ni atoms is 50 atomic% or more. 9. An average thickness of the brass plating is 0.13 to 0.1.
The rubber-steel cord composite according to any one of claims 1 to 8, wherein the thickness is 30 µm. 10. The rubber-steel cord composite according to claim 1, wherein the filament has a diameter of 0.40 mm or less.